My first attempt at doing something like this...utter failure. Full XT with 29er wheel set. Problem is I stripped a crank arm the first time I tried putting a pedal on it.
I cut off the threads to the pedal, cut the head off a bolt, welded the threads from the bolt to the pedal, and then re-tapped the crank arm. Apparently I didn't weld
the bolt directly center in the center and now I've ruined not only a crank arm but a set of pedals. It's very rideable but that in combination with the BB being too long
makes for an awful ride. I'm about to sell this and build up a gunnar crosshairs frame I stumbled upon.